Biodiesel synthesis via metal oxides and metal chlorides catalysis from marine alga Melanothamnus afaqhusainii

This research article demonstrates the most comprehensive comparative catalytic study of different metal oxides and metal chlorides towards the methanolysis of triglycerides of marine red macroalga Melanothamnus afaqhusainii.CaO was found to be the most reactive metal oxide that yielded 80% biodiesel while ZnCl_2 was the most reactive metal chloride that produced 60% biodiesel by mechanical stirring for 6 h at 100–110 °C.The overall reactivity order of the catalysts was found to be CaOMgOPbO_2ZnCl_2TiCl_4PbOHgCl_2ZnOAlCl_3SnCl_2TiO_2whereas,CaCl_2,MgCl_2,Al_2O_3,HgO,PbCl_2,MnO_2,MnCl_2,Fe_2O_3 and FeCl_3 were found to be non-reactive for transesterification of triglycerides.In addition,a detailed study of the screening of mobile phases and spraying reagents was conducted which showed that petroleum ether :chloroform :toluene(7:2:1)is the best mobile phase,whereas iodine crystals/silica gel is the best visualizing agent for the thin layer chromatography(TLC)examination of biodiesel.Biodiesel production was confirmed by comparative TLC examination.It was further supported by the determination of fuel properties of biodiesel,which were found to be similar to the standard limits of American Society for Testing and Materials(ASTM).     

Optimization of Two-Step Biodiesel Production from Beef Tallow with Microwave Heating

Animal fats are by-products from slaughterhouses that may be utilized as renewable energy source. This study was about biodiesel production from high free fatty acid beef tallow waste using two-step process with microwave heating. Sulfuric acid and NaOH were used as catalysts with methanol for the first esterification and second transesterification step, respectively. Catalyst loadings were between 0.25% and 2.5%, with applied microwave power of 340?W, operation time of 10–50?min, and oil-to-methanol molar ratio between 1:3 and 1:15. These process parameters were optimized using the design of experiments. The yields and properties of the biodiesel were assessed. The results indicated that the two-step process were successful in converting the beef tallow to biodiesel. Statistical analysis of the results showed that significant contributions were from the linear and quadratic terms of these three variables. The optimum conditions for esterification and transesterification were reported. Validity of the predicted models was confirmed by the experimental verification.     

Biodiesel production from tobacco (Nicotiana tabacum L.) seed oil with a high content of free fatty acids

The production of fatty acid methyl esters (FAME) from crude tobacco seed oil (TSO) having high free fatty acids (FFA) was investigated. Due to its high FFA, the TSO was processed in two steps: the acid-catalyzed esterification (ACE) followed by the base-catalyzed methanolysis (BCM). The first step reduced the FFA level to less than 2% in 25 min for the molar ratio of 18:1. The second step converted the product of the first step into FAME and glycerol. The maximum yield of FAME was about 91% in about 30 min. The tobacco biodiesel obtained had the fuel properties within the limits prescribed by the latest American (ASTM D 6751-02) and European (DIN EN 14214) standards, except a somewhat higher acid value than that prescribed by the latter standard (<0.5). Thus, tobacco seeds (TS), as agricultural wastes, might be a valuable renewable raw material for the biodiesel production.     

Comparison of Fatty Acid Methyl and Ethyl Esters as Biodiesel Base Stock: a Review on Processing and Production Requirements

Fatty acid methyl esters (FAME) were the first fatty acid esters to be introduced for use as biodiesel. However, there is a growing interest in the use of fatty acid ethyl esters (FAEE) in biodiesel. Both FAME and FAEE have their own unique advantages and disadvantages. These differences are ultimately attributable to the structural differences imparted by the alcohols used in their production. Sources of reactants as well as their safety issues, are a focus of this review. Also reviewed are the comparative characteristics and properties of both biodiesel types in terms of physicochemical features and performance. Processing requirements, reaction times and molar ratios of alcohol to oil, together with problems and drawbacks, are discussed. Recent developments on improving the yield of biodiesel, include mixing methanol and ethanol in the same reaction with ethanol acting as a co-solvent, and enzymatic methanolysis and ethanolysis are also highlighted.     

A Kinetic Study of Sunflower Oil Methanolysis Catalyzed by Barium Hydroxide

Methanolysis of sunflower oil was investigated in the presence of barium hydroxide as a catalyst. It was observed that the methanolysis reaction was both heterogeneously and homogeneously catalyzed. The heterogeneously catalyzed reaction is faster than the homogeneously catalyzed one and determines the overall reaction rate. Under optimum reaction conditions, a very high fatty acid methyl ester content was obtained within a few minutes. The barium hydroxide‐catalyzed methanolysis is faster than the methanolysis catalyzed by calcium oxide and calcium hydroxide and comparable to the potassium hydroxide‐catalyzed methanolysis.     

Muskmelon (Cucumis melo) seed oil: A potential non-food oil source for biodiesel production

Methanolysis of muskmelon seed oil was optimized employing RSM (response surface methodology). Four process variables were evaluated at two levels: methanol/oil molar ratio (3:1–12:1), catalyst concentration in relation to oil mass (0.25–1.25 wt % KOH), reaction temperature (25–65 °C) and methanolysis reaction time (20–90 min). Multiple regression analysis was employed to get the quadratic polynomial equation for predicting transesterification using RSM. The result indicated that catalyst concentration and reaction temperature were the important factors that significantly affect the yield of MMOMEs (muskmelon oil methyl esters)/biodiesel. The RSM methodology was used to obtain methyl esters yield (89.5%) were found at following reaction conditions; 5.8:1 methanol-to-oil ratio, 0.79% catalyst concentration, 55 °C reaction temperature and 72.5-min reaction time. There was a linear correlation between observed and predicted values. The biodiesel was analyzed using GC/MS (gas chromatography/mass spectrometry) which indicated four FAMEs (fatty acid methyl esters) (linoleic-, oleic-, palmitic- and stearic acids) as its major components. The FT-IR (fourier transform infraRed) spectrum of MMOMEs was also acquired to ensure the confirmation of methyl esters formation. Fuel properties of MMOMEs were determined and found to satisfy the ASTM D 6751 and EU 14214 specifications.     

Heterogenization of the biodiesel synthesis catalysis: CaO and novel calcium compounds as transesterification catalysts

Although CaO is one of the most studied basic heterogeneous catalysts for the synthesis of biodiesel, there are important issues that have been addressed by only a few research groups and that deserve further investigation. This is the case of the difficulties introduced by the poisoning of CaO upon exposure to ambient air and the role played by CaO-glycerol complexes on the catalytic performance. The purpose of this work is to provide new information on these issues in order to contribute to a better understanding of the underlying phenomena. Four commercial CaO samples have been considered to investigate their activation and stability under reaction conditions. In addition, calcium glyceroxide, and, for the first time, calcium glycerolate, have been synthesized and compared with the materials obtained from the commercial samples. The solids have been characterized with special emphasis on the assessment of their basic properties. The catalytic tests revealed big differences between the performance of the commercial solids that were substantially reduced after calcination and, specially, Ca-glyceroxide formation during reaction. Ca-glycerolate was the most resistant catalyst to ambient air although it was characterized by a low initial activity. Ca-glyceroxide could be reutilized for at least 5 reaction cycles without activity loss.     

Orange peel ash coated Fe3O4 nanoparticles as a magnetically retrievable catalyst for glycolysis and methanolysis of PET waste

Chemical recycling of PET offers the process of recovering virgin grade raw materials that can be reprocessed to produce an intact polymeric material or other valuable products. In the current study, we investigate the advantages of exercising biowaste derived orange peel ash (OPA) magnetic nano-catalyst, OPA@Fe₃O₄ as a green and reusable heterogeneous solid catalyst for glycolytic and methanolytic degradation of PET waste. The composition and physical features of the prepared catalyst were studied and analyzed using various techniques. Under the optimized condition, the catalyst was able to obtain an excellent bis(2-hydroxyethyl) terephthalate (BHET) and dimethyl terephthalate (DMT) yield with 100% PET conversion. Moreover, the catalyst was able to be recycled for ten consecutive runs for both processes without a significant reduction in the yield of the reaction, addressing the possible implementation of the catalyst for industrial purposes.     

Metal-free catalysts with phosphorus and oxygen doped on carbon-based on Chlorella Vulgaris microalgae for hydrogen generation via sodium borohydride methanolysis reaction

Metal-free catalysts (C–KOH–P) containing phosphorus (P) and oxygen (O) prepared by the modification with phosphoric acid (H₃PO₄) of activated carbon (C–KOH) obtained by activation of Chlorella Vulgaris microalgae with potassium hydroxide (KOH) were investigated for the hydrogen (H₂) generation reaction from methanolysis of sodium borohydride (NaBH₄). Elemental analysis, XRD, FTIR, ICP-MS, and nitrogen adsorption were used to analyze the characteristics of metal-free catalysts. The results showed that groups containing O and P were attached to the carbon sample. In the study, the hydrogen production rates (HGR) obtained with metal-free C–KOH and C–KOH–P catalysts were 3250 and 10,263 mL/min/g, respectively. These HGR values are better than most values obtained for many catalysts presented in the literature. Besides, relatively low activation energy (Ea) of 27.9 kJ/mol was obtained for this metal-free catalyst. The C–KOH–P metal-free catalyst showed ideal reusability with 100% conversion and a partial reduction in the H₂ production studies of NaBH₄ methanolysis after five consecutive uses.     

Phosphorus and oxygen doped carbon-based on Spirulina microalgae as efficient metal-free catalysts to obtain H2 from methanolysis of NaBH4

Metal-free catalysts (SP–KOH–P) doped phosphorus and oxygen as a result of modification with H₃PO₄ to the surface of the activated carbon sample (SP–KOH) obtained by activation of KOH with Spirulina microalgae were used to obtain hydrogen (H₂) from methanolysis of NaBH₄. The characteristic structure of SP-KOH-P and SP-KOH metal-free catalysts were examined by XRD, TEM, elemental analysis, FTIR, and ICP-MS. The effects of the amount of catalyst, NaBH₄ concentration, reusability, and temperature on H₂ production rate from NaBH₄ methanolysis reaction were investigated. The hydrogen production rate (HGR) obtained with 25 mg SP-KOH-P was found to be 19,500 mL min^?1 g^?1. The activation energy (Ea) value of SP-KOH-P metal-free catalyst sample was calculated as 38.79 kJ mol^?1.